1. Field of the Invention
The present invention relates to an improvement in a sheet-fed printing press equipped with a table for color checking of printed sheets.
2. Related Art
The sheet-fed printing press of the type is equipped with a table on which a printed sheet (printed matter) is placed for color checking thereof. This table will be hereinafter referred simply to a color check table. An operator picks up one of printed matters from a sheet discharge section and places the same on the color check table in order to compare the printed matter placed on the color check table with a reference printed matter (a color sample) to check registers, ink densities and so on. On the basis of the result of this checking, the amount of each ink is adjusted or corrected for example by controlling the opening degree of each ink fountain key.
The color check table for the above purpose is hitherto provided independently of a printing press body and therefore a space for the color check table must be separately provided. In order to omit the necessity to provide a separate space, Japanese Patent Application Laid-open No. 2001-80050 proposes an arrangement with the color check table disposed on the upper side of the sheet discharge section.
Although providing an advantage to omit the necessity to provide a separate space, the above arrangement with the color check table located on the upper side of the sheet discharge section does not allow a window to be provided on the upper side of the sheet discharge section. Or, the window is covered with the color check table provided on the upper side of the sheet discharge section. A window, which is provided on the upper side of the sheet discharge section to allow the operator to visually observe the ongoing sheet discharging process in printing operation, cannot be substantially used, if the color check table is located on the upper side of the sheet discharge section. The operator generally stands downstream to the printing press in order to perform his work such as adjusting the air supply to the sheet discharge section or checking whether stain or spot exists, while visually observing the ongoing sheet discharge process. Throughout the description, the terms, “upstream side” and “downstream side” are respectively used to represent a side closer to a sheet feed section and a side closer to a sheet discharge section with reference to the sheet transfer direction.
Accordingly, the sheet discharge section is provided with a window in order to check the ongoing sheet discharge process or check the quality of printed sheets upon visual observation of the inside of the sheet discharge section. In a case where the window is provided in a downstream sidewall of the sheet discharge section, the operator must frequently bend over to see the inside of the sheet discharge section through this window and also is hard to see the inside of the sheet discharge section through the window of the downstream sidewall. Therefore, it is preferable to solely provide the window on the upper side of the sheet discharge section or additionally provide another window on the upper side.
The arrangement with the window on the upper side of the sheet discharge section however poses the aforementioned problem. That is, the window is necessarily covered by the color check table disposed on the upper side of the sheet discharge section. In order to address this problem, the sheet discharge section may be designed to have a length large enough to accommodate both the color check table and the window respectively on the upstream side (a side closer to the printing press) and the downstream side thereto. This arrangement provides a high visual recognition capability, but poses a problem of deteriorating the operation efficiency in placing each printed sheet on the color check table. The reverse arrangement of the window and the color check table along the sheet transfer direction also poses a problem of deteriorating the visual recognition capability of the window.
In consideration of these problems, it is an object of the present invention to provide a sheet-fed printing press that is capable of securing a high visual recognition capability for the operator to observe the inside of the sheet discharge section, reducing the space for the color check table, as well as securing an excellent operation efficiency in placing each printed sheet on the color check table.